The main function of the engine timing belt is to drive the valve distribution mechanism of the engine, so that the engine inlet and exhaust valves can be opened or closed at an appropriate time to ensure that the engine cylinders can normally breathe in and exhaust. On some models, such as Volkswagen Jetta (EFI), Santana 2000, Bora, Audi, etc., the timing belt is also responsible for driving the water pump.
